Of the many illnesses that plague Americans, heart disease is the deadliest—and one of the toughest to predict. Epidemiologists have long used surveys and clinical data to tease out genetic factors from lifestyle risks such as diet, smoking, and stress, with little success. But a new study shows that there might be a better tool to assess heart disease: Twitter.

A study published in the peer-reviewed journal Psychological Science analyzed tweets and health data from 1,300 counties across the United States. The researchers found that negative tweets—those expressing fatigue, hostility, and stress—were associated with elevated risk of coronary heart disease (the medical term for clogged arteries) in the counties where the writers of those tweets lived. High volumes of tweets expressing optimism, excitement, ambition, and activity, meanwhile, correlated with lower than average rates of heart disease.

Here are some word clouds with examples of language that predicted higher and lower levels of disease:

Psychological Science

What's more, the researchers found that the language used in tweets correlates much more closely with heart disease rates than traditional predictive factors such as your income and education level, your weight, and even whether you are a smoker:

Psychological Science

Lead author Johannes Eichstaedt, a psychological scientist at University of Pennsylvania, described Twitter as "the perfect tool for figuring out something like heart disease." Researchers have long suspected connections between emotional states and heart disease risk. And while it's not surprising that people with high levels of stress and anger would be at higher risk than their mellower, happier peers, researchers have traditionally relied on surveys to evaluate people's psychological well being. The problem is that survey-based studies can take years, and people aren't always honest about their feelings. Which makes Twitter a researcher's treasure trove. "Twitter is where people talk about themselves, where they express their emotions candidly," Eichstaedt says.

Here's a map showing coronary heart disease deaths by county, using data from the Centers for Disease Control and Prevention:

Psychological Science, CDC

Now compare it with this map, which predicts rates of heart disease based on tweet language:

Psychological Science, Twitter

Another bonus of using Twitter as an epidemiological tool: It's much easier and cheaper than going door to door or calling people to conduct surveys. "If I wanted to repeat this analysis I could do it in an afternoon," says Eichstaedt. "With surveys, that would take a year."

Despite abundant evidence that flu vaccines are safe and effective, only about a third of Americans get the shots each season. Public health experts believe that one reason for the low immunization rates is misinformation about side effects of the vaccine. One is the belief that the vaccine can actually give you the flu (false); another is that it can cause autism in children (also false, as we've saidmanytimes).

"Your risk of GBS actually goes down when you get the vaccine because it prevents the flu."

Add that to the worry that it will cause a rare but serious nervous-system disorder called Guillain–Barré syndrome (GBS), an autoimmune disease in which the immune system attacks the nervous system, resulting in muscle weakness, or even temporary paralysis. This fear is not completely unfounded—several studies, including a recent one by Italian researchers about the 2010-2011 vaccine—have found that getting a flu shot can indeed very slightly elevate one's risk of contracting the disease, by about one additional case per million people.

But here's where things get complicated: While it's true that the flu vaccine can raise your GBS risk, so can the flu itself. So which is more likely to lead to GBS: Getting the vaccine or getting the flu?

That's the question that Steven Hawken and Kumanan Wilson, epidemiologists from The Ottawa Hospital, set out to answer. The researchers developed a calculator that took into account baseline GBS risk (overall, it's about 10 in a million, though it varies with age and sex—GBS affects more men than women and more elderly people than young adults and children), vaccine effectiveness, and overall incidence of flu. Their findings: For most people, in a flu season where the flu incidence is greater than 5 percent and the vaccine is more than 60 percent effective, says Wilson, "your risk of GBS actually goes down when you get the vaccine because it prevents the flu."

That's good news in most years, when the flu vaccine is well over 60 percent effective. Here's the problem: This year's flu vaccine is only about 23 percent effective. Still, according to Wilson, while this year's total flu incidence isn't yet known, it appears to be greater than that of an average year—much higher than 5 percent. That means that even with the reduced effectiveness of the vaccine, the overall GBS risk is likely still greater for people who contract the flu than for those who get immunized, says Wilson.

What's more, he adds, it's important to keep in mind that the risk of serious complications from the flu outweighs that of acquiring GBS. Last year, according to the CDC, 9,635 people were hospitalized with the flu in the United States. According to the CDC there are between 3,000-6,000 cases of GBS annually (though no hospitalization data is available). Most of those cases aren't caused by flu vaccines or the flu itself; the most common cause of GBS is infection with the bacterium Campylobacterjejeuni, usually the result of eating contaminated food.

The takeaway: The GBS risk from the flu itself is most likely greater than that of the vaccine. And while GBS can be a scary disease, it's much less common than scary complications FROM the flu.

As we all know, the internet is obsessed with bacon. Physicians, however, are usually less bullish about the delicious yet notoriously artery-clogging treat. Until now: Over at the medical blog KevinMD, Dr. Jennifer Gunter combs the scientific literature and turns up three actual medical conditions that bacon can help treat:

Nosebleeds. Last October, Stanford otolaryngologist Ian Humphreys developed a nasal tampon made out of bacon that cured a young girl's bloody nose, an accomplishment for which he was awarded a 2014 IgNobel Prize in medicine. "Apparently the high salt content of bacon is believed to induce swelling which causes the blood vessels to constrict slowing the flow of blood and helping clotting," writes Gunter. When Humphreys won the IgNobel, Robert Jackler, chair of Stanford's otolaryngology department, told Stanford's Scope medical blog, "We are squealing with pride."

An incredibly disgusting-sounding infection called furuncular myiasis in which the larvae of an insect called Dermatobia hominis nest in the human soft tissue or skin, resulting in boils and sometimes tissue destruction. Shudder. "The treatment largely consists of manually picking out the larvae with tweezers," writes Gunter. "Apparently bacon fat can be used as bait to lure the larvae to the skin surface for faster and more effective removal."

Scabies. Apparently, bacon fat was once used in topical sulfur and salicylic acid creams used to treat this itchy and highly contagious skin infection. A 1991 study compared the bacon fat formulation to the more modern cold cream version and finds, Gunter writes, that "while the cold cream combination was 100% effective versus 88 percent for the bacon fat base the authors noted that the bacon fat concoction was 238 times less expensive than the cheapest scabicidal medication in the U.S."

So there you have it: bacon as medicine. Something to keep in mind if you have any left over after you make that gross bacon lattice thing for your Super Bowl party.

Replacing clinic visits with smartphones can be a risky move. Here's why.

In 2013, when Julie Hudak read about an iPhone app that could diagnose skin cancer, she downloaded it right away. Her husband and sister-in-law had both died of melanoma, and she didn't want to miss any early signs of the disease in her three children. It was easy to use—simply upload a photo of a mole and get a color-coded result: Green meant cancer was unlikely, yellow was a maybe, and red indicated danger. Even though the dermatologist had assured Hudak just a week earlier that her children's skin looked fine, she decided to snap photos of her 11-year-old daughter's moles. Seconds later, the results appeared. "Some came up yellow, and one was red," Hudak recalls. "I panicked." She called the dermatologist for an emergency appointment.

And not just bigger—they're also sicker.

Thanksgiving turkeys are one of America's oldest holiday traditions. But with their giant size, stooped frame, and limited mobility, today's birds bear little resemblance to their early counterparts. So how did we end up with these modern megabirds? According to Suzanne McMillan, senior director of the farm animal welfare campaign of the American Society for the Prevention of Cruelty to Animals, it wasn't by accident.

The male turkeys, or toms, got so big—as heavy as 50 pounds—that they could no longer manage to transfer semen to hens.

Up until the the 1950s, turkeys found on Thanksgiving tables were essentially the same as their wild counterparts. But then, says McMillan, American poultry operations began to expand to meet Americans' growing demand for meat. Turkey farmers began to selectively breed birds for both size and speed of growth—especially in the breast, the most popular cut among American diners. The birds grew so fast that their frames could not support their weight, and as a result, many turkeys were bowlegged and could no longer stand upright. The male turkeys, or toms, got so big—as heavy as 50 pounds—that they could no longer manage to transfer semen to hens. Today, reproduction happens almost exclusively through artificial insemination.

At around the same time, producers also began moving their operations indoors, where they could fit more birds and ensure that they developed uniformly, so turkeys' feeding and care did not have to be individualized. In these close quarters, birds began to develop infections, like sores on their breasts and foot pads. To prevent these problems, and also to encourage growth, producers added low doses of antibiotics to the birds' feed. Also because of space limitations, birds became aggressive and often resorted to cannibalism. In response, hatcheries began trimming birds' beaks—known as debeaking—when they were a few days old.

If all of this makes turkey sound unappetizing, consider the latest development: As of October 20, turkey slaughter facilities were allowed to speed up their lines from 51 to 55 birds per minute—while also reducing the number of federal inspectors, as my colleague Tom Philpott has reported.

Consumer demand for cheap turkey has fueled these trends. The National Turkey Federation reports that turkey consumption has doubled over the last 30 years—today, the average American eats 16 pounds of turkey per year. Meanwhile, turkey prices haven't increased much; in fact, this year turkey is cheaper than last year. Reuters reported that some grocery chains "use turkeys as 'loss leaders' to entice shoppers to buy other popular Thanksgiving foods."

No wonder, then, that we end up trashing a lot of turkey:

By Jaeah Lee

If you don't want to support turkey factory farms, McMillan says, look for birds that are certified through animal welfare programs. Grist has a good guide to picking a turkey with real humane bona fides here. A word of caution, though: This year, turkey giant Butterball says it has gone humane, but as Philpott reports, it so far hasn't ditched many of the most cruel practices.